[Project 1] Results and future plans | Climate Change Research Program

Project 1Characteristics of the variation of greenhouse gas concentrations and projections for the future

Results and future plans

Thanks to global observations by satellite, it has become possible to estimate column averaged CO₂ volume mixing ratios. Using satellite data as well as data obtained in the current project, we develop techniques to estimate the distribution of CO₂ fluxes. Figure 1 shows the world divided into 68 estimation areas.

Figure 1.68 flux estimation areas

It was found that data obtained over India and Southeast Asia by aircraft measurements gave us new information on regional CO₂ fluxes around there, since reliable data were not previously available in those areas. We hope to be able to obtain even more detailed data in the near future. It has been shown that the data on the vertical distribution of CO₂ obtained by aircraft observations, in combination with data from ground-based monitoring stations, provide extremely good information on global mixing patterns in the atmosphere. There had been almost no information about the mixing of air between the northern and southern hemispheres, but through the aircraft observations in our project the mixing patterns have been clarified.

Figure 2.Vertical distribution of CO₂ at different altitudes

Since not only anthropogenic combustion of fossil fuels, but also other phenomena such as forest fires can be a source of CO₂ emissions, it is thought that observing carbon monoxide (CO) and methane (CH₄) could give a good indication of CO₂ emission sources in Southeast Asia. Therefore, data obtained by high frequency ship-based observations in recent years will be able to provide valid information. Figure 3 shows the distribution of CO concentrations obtained by ship-based observations, reflecting the regional distribution of CO emissions originating from forest fire in Southeast Asia.

Figure 3.CO measurements by regular ship service on the Asian route between December and February

In the current project, we undertake also observation of terrestrial and oceanic CO₂ fluxes. Especially for the Pacific Ocean we develop CO₂ flux maps with even higher accuracy. By integrating the observations in the atmosphere and flux measurements we aim to further improve the estimation accuracy of global CO₂ fluxes.

Figure 4.Pressure distribution of CO₂ above the ocean estimated by neural network